Variación estacional de la temperatura y salinidad en la entrada del Golfo de California, México
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Authors
Castro, Rubén
Mascarenhas, Affonso S.
Durazo, Reginaldo
Collins, Curtis A.
Subjects
Golfo de California
seasonal variation
variación estacional
Gulf of California
thermohaline properties
propiedades termohalinas
El Niño
seasonal variation
variación estacional
Gulf of California
thermohaline properties
propiedades termohalinas
El Niño
Advisors
Date of Issue
2000
Date
Publisher
Language
Abstract
Se describe la variabilidad estacional en la entrada al Golfo de California utilizando datos de CTD en
una sección a través de la entrada al golfo, la cual fue ocupada en ocho ocasiones entre 1992 y 1998. Se
encontró que la variabilidad decrece rápidamente debajo de los 100 dbar; las desviaciones estándar
mayores que 0.5ºC y 0.05 para temperatura y salinidad, respectivamente, fueron confinadas a la capa
superior de 150 dbar. El campo medio de salinidad fue asimétrico, con aguas de menor salinidad
(S <34.6) entre 25 y 75 dbar cerca de Sinaloa y aguas de mayor salinidad (S > 34.8) arriba de 50 dbar y
entre 100 y 150 dbar cerca de Baja California. En la capa superior de 50 dbar se observó una termoclina
estacional sobre la cual las temperaturas superficiales cambiaron de 21ºC en febrero a 31ºC en agosto.
Debajo de los 100 dbar, la temperatura a una presión dada fue típicamente más fría en el centro de la
sección, indicando flujo ciclónico (flujo de entrada al golfo cerca de Sinaloa y de salida del golfo cerca de
Baja California). El enfriamiento subsuperficial en la mitad de la sección del golfo (flujo ciclónico) fue
más fuerte durante el invierno y la primavera, época cuando el intercambio de calor entre el golfo y el
Océano Pacífico es mayor. No se observó el calentamiento subsuperficial en la parte media de la sección
que corresponde a un flujo anticiclónico. La distribución temporal y espacial de las masas de agua de
mayor salinidad sugieren que los intercambios de calor se dan por la alternancia de flujos de entrada y
salida de masas de agua de mayor temperatura (superficial) y menor temperatura (subsuperficial). Durante el evento de El Niño 1997–1998 se observó un hundimiento de 50 dbar en la termoclina en
noviembre de 1997, así como una disminución de 0.1 a 0.2 de la salinidad de las aguas arriba de la
termoclina.
Seasonal variability at the entrance to the Gulf of California is described using high resolution CTD data from a section across the entrance to the gulf that was occupied eight times between 1992 and 1998. Variability decreased rapidly below 100 dbar, so that standard deviations exceeding 0.5ºC and 0.05 for temperature and salinity, respectively, were confined to the upper 150 dbar. The mean salinity field wasasymmetric, with fresher waters (S < 34.6) between 25 and 75 dbar next to Sinaloa and saltier waters (S > 34.8) above 50 dbar and between 100 and 150 dbar near Baja California. A seasonal thermocline developed in the upper 50 dbar, increasing from 21ºC in February surface temperatures to 31ºC in August. Below 100 dbar, temperature at a given pressure was typically colder in the center of the section, indicating cyclonic flow (flow into the gulf next to Sinaloa and out of the gulf next to Baja California). The subsurface mid-gulf cooling (cyclonic flow) was strongest during winter and spring when the exchange of heat between the gulf and the Pacific Ocean is large. Subsurface mid-gulf heating (corresponding to anticyclonic flow) was not observed. Temporal and spatial distribution of saline water masses suggests that heat exchanges take place by alternating the inflow and outflow of warm (surface) and cold (subsurface) water masses. The 1997–1998 El Niño resulted in a 50 dbar deepening of the thermocline in November 1997, as well as a freshening of 0.1 to 0.2 of waters above the thermocline.
Seasonal variability at the entrance to the Gulf of California is described using high resolution CTD data from a section across the entrance to the gulf that was occupied eight times between 1992 and 1998. Variability decreased rapidly below 100 dbar, so that standard deviations exceeding 0.5ºC and 0.05 for temperature and salinity, respectively, were confined to the upper 150 dbar. The mean salinity field wasasymmetric, with fresher waters (S < 34.6) between 25 and 75 dbar next to Sinaloa and saltier waters (S > 34.8) above 50 dbar and between 100 and 150 dbar near Baja California. A seasonal thermocline developed in the upper 50 dbar, increasing from 21ºC in February surface temperatures to 31ºC in August. Below 100 dbar, temperature at a given pressure was typically colder in the center of the section, indicating cyclonic flow (flow into the gulf next to Sinaloa and out of the gulf next to Baja California). The subsurface mid-gulf cooling (cyclonic flow) was strongest during winter and spring when the exchange of heat between the gulf and the Pacific Ocean is large. Subsurface mid-gulf heating (corresponding to anticyclonic flow) was not observed. Temporal and spatial distribution of saline water masses suggests that heat exchanges take place by alternating the inflow and outflow of warm (surface) and cold (subsurface) water masses. The 1997–1998 El Niño resulted in a 50 dbar deepening of the thermocline in November 1997, as well as a freshening of 0.1 to 0.2 of waters above the thermocline.
Type
Article
Description
The article of record as published may be found at http://dx.doi.org/10.7773/cm.v26i4.621
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
CONACYT
UABC
Oceanographer of the Navy (US)
Naval Postgraduate School
Secretaría de Marina
UNAM (Mexico)
UABC
Oceanographer of the Navy (US)
Naval Postgraduate School
Secretaría de Marina
UNAM (Mexico)
Funder
26653-T
4271P-T9601
4009
4015
1076-T9201
4271P-T9601
4009
4015
1076-T9201
Format
23 p.
Citation
Castro, Rubén, et al. "Seasonal variation of the temperature and salinity at the entrance to the Gulf of California, Mexico." Ciencias Marinas 26.4 (2000): 561-583.
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States